With a few notable exceptions, the European Union's diplomatic representation in the US has long been a refuge for backroom bureaucrats with tin ears and thick continental accents. The appointment of John Bruton as the new EU ambassador in Washington signals that change is in the air.

Tall, silver-haired, with twinkling eyes and a politician's girth, Bruton is a born salesman with a passion for Europe. He has spent a lifetime in the Dáil, the lower house of the Irish parliament, 35 years in all, as well as a spell as taoiseach [prime minister] of the Irish Republic. He is a heavyweight in every sense of the word.

We have chosen to lunch in one of the capital's power restaurants: Smith & Wollensky's, the steakhouse on 19th Street, where the waiters are liveried and the host talks like Jason Robards in All the President's Men. Bruton arrives slightly late, bearing apologies. It is still only 12.30pm. I am dug in for a long lunch, Brussels-style.

We have much to talk about - Bruton's proud Irish roots, (till now he's never left his home in Dunboyne, County Meath), Britain's troubled history with Europe, America's awkward relationship with Europe, and, of course, President George W. Bush, whom Bruton met a few days before when he presented his credentials at the White House. But we must order food, or rather drinks.

"Whisky sour, if I may," says Bruton, scrutinising the menu. He plumps for the prime rib. Coming from a family of farmers and cattle dealers going back at least as far as the Irish famine in the mid-19th century, he confesses to being partial to beef. I order crab cakes and a Caesar salad.

So how did he land his new job? "It happened back in July 2003 in the Dáil. Bertie Ahern [the taoiseach] slipped me a note saying he would like a word. Romano Prodi [then president of the European Commission] had telephoned that day. My name had been mentioned about a job. I was an opposition frontbencher without portfolio so I accepted instantly."

Almost 18 months later, Bruton has finally arrived in Washington. Insiders blame the delay on resistance from one or two national capitals, which wanted the plum post for one of their own. But Prodi stuck to his guns. He was quietly encouraged by Chris Patten, his fellow EU commissioner and now chancellor of Oxford University, who had the original idea. Both Patten and Prodi were determined to raise Europe's profile in Washington.

Officially, Bruton is merely head of the delegation of the European Commission, the EU's much-maligned executive branch in Brussels. In practice, as the EU's ambassador, he represents the collective interests of the 25 member states. But he must also jockey for access and influence in Washington with the national ambassadors, many of whom jealously guard their special relationships with the US.

This requires a delicate balancing act. But having entered the Dáil at the tender age of 22, Bruton knows how to play politics. He is not the first prime minister to occupy the job. An obscure Dane and a perfectly pleasant Dutchman previously held the post. But he is the first real "pol" and that should go down well on Capitol Hill. "I have stared down the barrel of a gun. I know what it is like to run for re-election. I can relate to these guys."

Bruton's other strength is his Irish background. There are around 40m Americans of Irish heritage. A number have recently reached the top of US business, a useful circle of influence. Many Americans have also taken a close interest in the Irish peace process, which Bruton pursued when taoiseach between 1994-1997.

Bruton's first task is to manage the EU mission, ensuring accurate and timely reports to his new masters in Brussels. A trained lawyer, he has few fears about mastering his briefs, which range from Airbus subsidies to international accounting standards, and corporate governance. ("I am a policy wonk, that was half my problem in Ireland.") His big challenge is to sell the EU to a sceptical American audience.

While academic interest in the EU has risen in the past decade, thanks to the launch of the euro and enlargement of the union to central and eastern Europe, Washington is still a bastion of ignorance. Senior officials complain about the EU's byzantine decision- making; the absence of a coherent negotiating partner (with the notable exception of competition policy and trade); and, above all, the windy rhetoric about creating a European superpower to rival the US.

Bruton is a true believer in Europe because Ireland has so obviously benefited from EU membership. The Irish walk tall, partly because EU membership has allowed them to escape the shadow of their British neighbour. But also because Ireland, once dubbed the leprechaun on steroids, has lately enjoyed economic prosperity without parallel in its history.

As a former finance minister, Bruton contributed to the Irish miracle by reining in public spending in the 1980s. ("We stopped Ireland from going down the plughole. We were heading for Argentine status.") But, he says, the decisive factor in Ireland's explosive growth was demographic: large numbers of emigrants returning home as Ireland slowly shed its stifling rural tradition and embraced modernity.

Inevitably, Bruton contrasts his country's embrace of the EU with Britain's lukewarm attitude. He worries that the British public will vote against the EU's new constitutional treaty in the upcoming referendum. "This is not about Britain being more competitive or outsmarting the rest of the EU. There needs to be a complete reconfiguring of the debate, starting with [next year's] election campaign."

The waiter arrives with the prime rib, a huge slab of meat and bone that provokes the famous Bruton laugh - a nervous whinny that finally dissolves into a beatific smile. He finishes his first glass of red wine and orders a second. I follow suit, opting for Sauvignon Blanc to accompany the crab cakes. It is time to begin the main discourse on transatlantic relations.

I ask Bruton about his first impressions of Bush. He chooses his words carefully.

"Clearly there is a strong reliance on what is instinctively right and wrong . . . but Europeans can penetrate the American debate. We just have to translate European into American."

Language is obviously crucial, so I ask him about Mr Bush's use of religious language, notably his statement that he seeks divine guidance. "That was rhetoric for a particular audience. Clearly the president is not seeking God's advice on where to locate air strikes. Europeans are reluctant to use religious images."

Bruton shifts ground. "Rather than drawing conclusions, we should ask ourselves what is President Bush telling us. Are we saying that there is no such thing as evil in the world? And if there is such a thing, what is wrong with using the world evil?"

I mention that I met Bush for two hours in May 2001, as part of a small group invited to brief the president ahead of his inaugural trip to Europe. Bruton is intrigued and asks for my impressions. I reply that he was crisp, courteous and much more Texan than I might have imagined. One memorable moment was when he dismissed the Kyoto treaty on the environment as "Murrrsh."

"He was half right," Bruton replies, emitting another nervous whinny.

We move to Iraq, still an uncauterised wound in the transatlantic relationship. Bruton is sanguine about the prospects for a successful transition to a democracy. He stresses the importance of an independent judiciary as the guarantor of the rule of law.

"We have to realise where we are now on Iraq: even if the US had the commitment of the French, Germans, Italians and Spanish, it would not change the fundamental equation. We need practical answers: what do Iraqi people need, how can the rest of the Arab world help, can we work with the Arab League?"

I ask if Iran risks turning into a re-run of the EU-US divide over Iraq. Once again, Bruton leans towards "soft power" solutions to deal with Iran's nuclear ambitions rather than the application of hard military power. At one point, he compares the vibrancy of Iranian youth with Ireland's own youth.

"Without creating a confrontation, we should bring this [vibrancy] to the surface, not in opposition to the west, but characteristically with an Iranian adaptation as to what is good about the west . . . Iran could also be drawn into the World Trade Organisation."

Bruton acknowledges the danger of nuclear weapons, but says the real threat is proliferation, with loose nukes falling into the hands of non-state actors. I counter that the Iranian regime has been accused by Washington of state-sponsored terrorism. Bruton needs no lessons in terrorism, having suffered a personal loss in Ireland. But for the first time in the lunch, he sounds less than convincing, waffling about "looking at matters in a holistic way".

We are approaching the end of an epic meal. As we sip our last drinks, I venture that Americans will only take Europe seriously when it is more practical, more relevant and more capable of projecting military power. Or as one former US ambassador in Brussels put it: the true test of a united Europe will be when Europeans are ready to fight and, if necessary die, for a cause under a European flag.

Bruton demurs, saying it is unfair of Americans to expect Europe to be something they have long been discouraged from being. Besides, the British, French and Poles were "bled white" in two world wars. In the Great War of 1914-18, the Irish lost 49,000 out of a population of 4m.

Yet Europeans must adjust their own expectations of America. "We judge Americans by more severe standards. We somehow expect them to be on a higher plane."

It is time, he says, to establish a new relationship. This cannot yet be a partnership of equals. But if Bruton has his way, it will be at least be a partnership based on mutual respect.